Buttons next to each other but still centered

Good day. I have searched the forums and cannot find answers. I have two button related questions.

1) How do you have two buttons appear next to each, but remain centered? I tried using the following code, which was successful in having the buttons appear next to each other, but then they get left-justified. How do I keep them next to each AND let the two buttons be centered while on the same line?

.avia-button-center
{
display: inline; padding: 0 5px;
}

2) How do I add an icon to the left of a button that is on the Full Width Easy Slider? Is there a CSS class for buttons specifically on the Full Width Easy Slider that I need to utilize?

Many thanks to you!